Means to eject sludge from centrifugal separators



' M. BARAM Filed May 6, 1963 ENTOR.

Oct. 25, 1966 MEANS TO EJECT SLUDGE FROM CENTRIFUGAL SEPABATORS UnitedStates Patent 3,281,068 I MEANS T0 EJECT SLUDGE FROM 'CENTRIFUGALSEPARATORS Martin Baram, Svanholmsvej No. 13, Vallensbaek, Denmark FiledMay 6, 1963, Ser. No. 278,134 2 Claims. (Cl. 233-20) The presentinvention relates to a new method in the intermittent or continuousejection of sludge from centrifugal separators.

In general the known separators include a vertical axis on which acentrifugal bowl is mounted for rotation, said bowl being divided :by anunbroken peripheral slit into an upper and a lower section. Theseparator includes an axially displaceable annular member that eithersurrounds said lower section or is mounted concentrically in the same.This annular member or piston is made of metal, generally steel, andposes a number of serious drawbacks.

First, a displaceable annular member moving either inside or outside thecentrifugal bowl must be tightened against leakage along its entirecontact surface, and at the same time both the displaceable member andthe relevant parts of the bowl must be machined to a very fine toleranceat their respective contact surfaces.

Secondly, a displaceable annular member represents a considerable partof the overall weight of the separator, thus demanding strongerconstructional features, and diminishing the separators capacity.

The object of this invention is to provide a separator apparatus whichpermits the ejection of the accumulated sludge from a known centrifugalbowl without employing any machined metallic piston member at all.According to the invention the opening and closing of the peripheralslit is effected by one or more elastic and flexible sealing organs,suitably shaped and suitably placed in or around the peripheral slit.

According to one embodiment of the invention, the sealing organ consistsof a ring made of rubber or similar material which is placed in anannular groove inside the pheripheral slit, said ring being in an openposition relative to the slit as long as the centrifugal bowl is notrotating, but being expandable under the influence of the centrifugalforce to close the slit, said sealing organ to be dimensioned andlocated in such a manner that it will be forced to uncover the slit by apredetermined hydrostatic pressure inside the bowl, thus permitting anintermittent ejection of sludge or similar separated material.

Another embodiment of the present invention provides for a hollowsealing organ shaped similar to a tubeless tire and attached watertightto an annular groove inside the slit, said sealing organ being in anopen position relative to the slit when the centrifugal bowl isstationary, and displaceable, by centrifugal force, to a closed positionrelative to the slit when the bowl is rotating. The sealing organ isfurther operable to uncover the slit to eject sludge when the supply offluid is stopped and as soon as the fluid present in the separator isevacuated through one or more outlets in the annular groove.

Both the above mentioned sealing organs and other embodiments of thepresent invention can be provided with a protecting cover to shield therelatively sensitive elastic sealing organ against the abrasive,corroding or similar action of the ejected material.

The invention will be described in more detail with reference to theaccompanying drawings in which:

FIGURES 1 and 2 are detailed vertical sectional views of two embodimentsof the separator of the present invention; and

FIGURES 3 and 3a are detailed vertical sectional views of a thirdembodiment of the invention, the sealing means being illustrated in theopen and closed positions, respectively.

Referring now to FIGURE 1, between an upper section 1 and a lowersection 2 of a centrifugal bowl is a peripheral ejection slit 3. Thecentrifugal bowl rotates on a spindle 6 and contains a plurality ofdiscs 5 of which only one is shown. Referring to FIG. 1 it will be seenthat an expanded sealing organ 4 closes slit 3. Owing to the centrifugalforce of the rotating bowl and its own elasticity the sealing member 4has been forced out of a groove 8 in which it is embedded when notsubjected to centrifugal forces, and into which it will be pushed backby separated sludge -or similarly plastic material when a predeterminedhydrostatic pressure inside the bowl has been reached, thus giving wayto intermittent sludge ejections. One or several vents 7 serve toevacuate that fluid or sludge which enters the groove.

Turning to FIG. 2 there will be seen a hollow sealing body 4' which ismounted at an angle within a groove 8 to define an annular chamber intowhich open a number of channels 9' for the supply of a fluid which maysuitably be injected directly into a funnel recess 10, or through a bore11 in spindle 6 as shown in FIG. 3. As long as the fluid is supplied thehollow sealing organ 4 will be inflated as shown in FIG. 2, therebycovering the slit 3'. When the supply of fluid is stopped the fluidpresent in the groove is evacuated through vents 7, thus permittingorgan 4 to be pulled away from slit 3 both by the centrifugal forceowing to its tilted position, and by its own elasticity when regainingits original shape. Thus the accumulated sludge can be ejected at will.According to the present invention it is also feasible to balance thesupply of the fluid to groove 8a and its evacuation through vents 7' insuch a manner that at a predetermined hydrostatic pressure inside thebowl an automatic sludge ejection will occur for as long as sealingorgan 4' is forced to yield to this pressure.

Turning to FIG. 3 there will be seen a hollow sealing body 4" mountedwithin a groove in an upright position, ,and covered by a protectingannular cover R which may either lie freely on top of sealing body 4" orbe attached to it in a suitable manner, as long as it permits the freemovement of cover R under the influence of the inflated sealing body 4"as shown in FIG. 3a. In this case the sealing body 4" must be made of asufliciently elastic material to make sure that it regains its originalshape as shown in FIG. 3, as soon as the inflating supply of fluid isstopped, and the fluid present in groove 8" has been evacuated throughvents 7". The supply of fluid is shown to pass from a bore 11 in spindle6" into the channels 9". However, it is also possible to supply thefluid as shown in FIG. 2. Furthermore, according to the invention aprotecting cover R of suitable shape may be suitably attached to thesealing organs as shown in FIGS. 1

and 2 as well as to any other sealing organ covered by the presentinvention.

While in accordance with the provisions of the patent statutes, the bestforms and embodiments of the invention have been illustrated anddescribed, it will be apparent to those skilled in the art that changesmay be made in'the apparatus described without deviating from theinvention set forth in the following claims.

What I claim is:

1. A rotary centrifugal separator, comprising a centrifugal bowl adaptedfor rotation about a vertical axis and including upper and lowersections having opposed horizontal annular edge surfaces spaced by acontinuous uniform gap lying generally in a horizontal plane, said gapbeing adapted to transmit sludge radially outwardly from said bowl, thean- .tion defining ,said gap, said cover member 'being discontainingpassage for supplying fluid to said chamber and at least one ventpassage for discharging fluid from said chamber, the inner and outeredges of said sealing member being secured to the Walls of said grooveand the central portion of said sealing member. being expansi-ble, .as afunction of the pressure of'the fluid in said chamber, froma-normallyretracted position relative to said gap when said bowl is stationary toan extended position completely closing said gap when said bowlisrotating. 7 i

2. Apparatus as defined in claim 1,' and further including an annularcover member of wear resist-ant material at least partiallymounted insaid groove-between said sealing member and that edge surface of saidbowl secplaceable by said sealing member between open and closedpositions relative to said gap.

References Cited by the Examiner UNITED STATES PATENTS Meer 233-47Macklind 233-2O 'Bath 233-20 Bjornstjerna 233-20 Milton.

Ayres 233-20 Harstick 233-20 Strich.

Steinacker 233-20 Sharples f 233-20 FOREIGN PATENTS M. CARY NELSON,Primary Examiner.

HENRY T. KLINKSIEK, Examiner.

1. A ROTARY CENTRIFUGAL SEPARATOR, COMPRISING A CENTRIFUGAL BOWL ADAPTEDFOR ROTATION ABOUT A VERTICAL AXIS AND INCLUDING UPPER AND LOWERSECTIONS HAVING OPPOSED HORIZONTAL ANNULAR EDGE SURFACES SPACED BY ACONTINUOUS UNIFORM GAP LYING GENERALLY IN A HORIZONTAL PLANE, SAID GAPBEING ADAPTED TO TRANSMIT SLUDGE RADIALLY OUTWARDLY FROM SAID BOWL, THEANNULAR EDGE SURFACE OF ONE OF SAID SECTIONS CONTAINING A CONTINUOUSANNULAR GROOVE; AND A FLEXIBLE RESILIENT ANNULAR SEALING MEMBER MOUNTEDIN SAID GROOVE TO DEFINE A CONTINUOUS ANNULAR CHAMBER, SAID ONE BOWLSECTION CONTAINING AT LEAST ONE SUPPLY PASSAGE FOR SUPPLYING FLUID TOSAID CHAMBER AND AT LEAST ONE VENT PASSAGE FOR DISCHARGING FLUID FROMSID CHAMBER, THE INNER AND OUTER EDGES OF SAID SEALING MEMBER BEINGSECURED TO THE WALLS OF SAID GROOVE AND THE CENTRAL PORTION OF SAIDSEALING MEMBER BEING EXPANSIBLE, AS A FUNCTION OF THE PRESSURE OF THEFLUID IN SAID CHAMBER, FROM A NORMALLY RETRACTED POSITION RELATIVE TOSAID GAP WHEN SAID BOWL IS STATIONARY TO AN EXTENDED POSITION COMPLETELYCLOSING SAID GAP WHEN SAID BOWL IS ROTATING.